Field of the Invention
A disclosure of this specification relates to the RF structure of a terminal supporting all of an inter-band carrier aggregation, an intra-band carrier aggregation, and various radio access technologies.
Related Art
3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) that is an advancement of UMTS (Universal Mobile Telecommunication System) is being introduced with 3GPP release 8. In 3GPP LTE, OFDMA (orthogonal frequency division multiple access) is used for downlink, and SC-FDMA (single carrier-frequency division multiple access) is used for uplink. To understand OFDMA, OFDM should be known. OFDM may attenuate inter-symbol interference with low complexity and is in use. OFDM converts data serially input into N parallel data pieces and carries the data pieces over N orthogonal sub-carriers. The sub-carriers maintain orthogonality in view of frequency. Meanwhile, OFDMA refers to a multiple access scheme that realizes multiple access by independently providing each user with some of sub-carriers available in the system that adopts OFDM as its modulation scheme.
Recently, the development of 3GPP LTE-A (LTE-Advanced), that is, the evolution of 3GPP LTE, has been completed.
In accordance with the LTE-A, a Carrier Aggregation (CA) technology in which a plurality of bands is grouped into one has been proposed. The CA technologies, as described above, may be generally separated into an inter-band CA technology and an intra-band CA technology. The inter-band CA is a method of aggregating and using Component Carriers (CCs) that are present in different bands, and the intra-band CA is a method of aggregating and using CCs in the same frequency band.
However, in the design of the RF structure of a user terminal, to support all of the intra-band CA, the inter-band CA, and existing several radio access technologies was impossible because the implementation of the intra-band CA, the inter-band CA, and existing several radio access technologies is very complicated.
Furthermore, if both the intra-band CA and the inter-band CA are implemented, there is a problem in that transmission power and reception sensitivity are reduced due to additional several devices.